Background: Suicide ranks as the third leading cause of death among youth aged 15-24 years. Schools provide ideal opportunities for suicide prevention efforts. However, research is needed to identify programs that effectively impact youth suicidal ideation and behavior. This study examined the immediate and 3-month effect of Surviving the Teens[R] Suicide Prevention and Depression Awareness Program on students' suicidality and perceived self-efficacy in performing help-seeking behaviors. Methods: High school students in Greater Cincinnati schools were administered a 3-page survey at pretest, immediate posttest, and 3-month follow-up. A total of 1030 students participated in the program, with 919 completing matched pretests and posttests (89.2%) and 416 completing matched pretests and 3-month follow-ups (40.4%). Results: Students were significantly less likely at 3-month follow-up than at pretest to be currently considering suicide, to have made a suicidal plan or attempted suicide during the past 3 months, and to have stopped performing usual activities due to feeling sad and hopeless. Students' self-efficacy and behavioral intentions toward help-seeking behaviors increased from pretest to posttest and were maintained at 3-month follow-up. Students were also more likely at 3-month follow-up than at pretest to know an adult in school with whom they felt comfortable discussing their problems. Nine in 10 (87.3%) felt the program should be offered to all high school students. Conclusions: The findings of this study lend support for suicide prevention education in schools. The results may be useful to school professionals interested in implementing effective suicide prevention programming to their students. (Contains 5 tables.)